Cooling filter for cigarettes and smoking articles

ABSTRACT

An integral cooling and filtering device designed to be fitted on a smoking end of a cigarette or other smoking article is provided to reduce the temperature of smoke produced by combustion of smoking material and to filter the cooled smoke prior to contact with a smoker&#39;s mouth. The device is configured with a receptacle to hold a cigarette or like smoking article and a mouthpiece section that directly contacts the smoker&#39;s mouth. A cooling section and a filter section are positioned between the receptacle and the mouthpiece section. Temperature reduction of the smoke is provided by a thermionic cooling means. The filter section can include a substantially permanent cleanable filter or a replaceable filter. The mouthpiece section may be a heat-resistant metal, a plastic, or another appropriate mouth contact material, while the receptacle and cooling and filtering sections are preferably formed of a suitable metal.

PRIORITY CLAIM

This application claims priority from U.S. Provisional Patent Application No. 61/617,034, filed Mar. 28, 2012, the disclosure of which is fully incorporated herein.

TECHNICAL BACKGROUND

The present invention relates generally to filtering elements and devices for cigarettes and other smoking articles, including cigars, pipes, and the like, and specifically to a filter element designed specifically to effectively cool hot combustion products produced by burning the smoking material in the cigarette or other smoking article and effectively filter undesirable constituents from the smoke.

BACKGROUND OF THE INVENTION

Although the number has decreased in recent years, a sizable portion of the world's population smokes cigarettes and other smoking articles and/or devices, including cigars, pipes, and hookas. Advances in the manufacture of cigarettes and other smoking articles have reduced the levels of tar, nicotine, and other harmful components produced by burning tobacco. Efforts to achieve further reductions of these substances have encompassed a range of approaches from modifications in the tobacco itself to changes in the cigarettes and other articles being smoked.

Filters have long been used on cigarettes to reduce the tar and nicotine in the smoke that actually reaches a smoker's mouth. These constituents of tobacco smoke are, ideally, adsorbed or trapped by the filter material so that the smoke inhaled by the smoker contains only what has not been adsorbed or trapped. A recent study, however, indicated that high temperatures present in the filter, especially during frequent puffing and while the cigarette is smoldering, can negatively affect adsorption of smoke constituents. In addition, adsorbed smoke constituents were also partly desorbed when filters contained carbon. Low tar cigarettes, in particular, demonstrated a significant temperature rise when smoked under intense conditions equated with frequent puffing.

Holders for cigarettes and cigars have long been available. Such holders have ranged from a relatively simple extension of an unfiltered cigarette that prevented the smoker from contact with loose tobacco to more complex structures capable of filtering the smoke. Some of these commercially available holders are intended to function as permanent filters with metal components that can be cleaned. Others include a replaceable disposable filter element. A holder for cigarettes and cigars is described in U.S. Pat. No. 3,323,525 to Miller that includes a heat resistant metal tubular sleeve that holds the cigarette or cigar and a plastic mouthpiece adapted to be held in a smoker's mouth. A series of passageways in the holder is positioned to draw outside air into the holder to reduce the temperature of the tobacco combustion products, thereby reducing the amount of tar that passes through the holder to the smoker's mouth. If the passageways become clogged with deposits of tar or other combustion products, however, effective cooling and tar reduction are not likely to occur.

Various modifications to cigarettes, primarily to cigarette filters, have been proposed to enhance the adsorption of harmful and undesirable smoke constituents. For example, in U.S. Pat. No. 4,865,056, Tamaoki et al describes a water-filled breakable capsule in a filter end of a cigarette, preferably positioned between a pair of filter elements, one of which is formed of hydrophobic fibers. The capsule is broken by squeezing the area of the cigarette above the capsule, which releases the water to impregnate the filter material. Since nicotine and tar are water soluble, they are dissolved in the wet filter when the cigarette is lighted and smoke is inhaled through the filter. Cooling the filter material is not mentioned. Dube et al, in U.S. Patent Publication No. US2011/0023896, describes a filtered cigarette with breakable capsules that can contain moistening or cooling agents. These moistening and/or cooling agents, however, are disclosed to be eucalyptus and menthol, which do not have an actual cooling effect on the filter itself.

Niederman describes the cooling of smoke in advance of filtration to obtain more complete filtering in U.S. Pat. No. 2,827,903. A metal foil radiating device with a series of small passages is provided within the cigarette so that heat in the smoke is transferred to the metal foil and some of the objectionable ingredients in the smoke are deposited in the passages before the smoke enters the filter. This is indicated to direct cleaner, lower temperature smoke to the filter. The placement of the metal passages close to the circumference of the cigarette is stated to allow heat to dissipate to the atmosphere through the cigarette wrapper. Heat dissipation is not likely to occur as effectively if the metal passages must be located close to the interior of the cigarette. Starbuck et al describe a heat sink structure incorporated within the body of a cigarette in U.S. Pat. No. 3,494,366 that can be used to cool and remove impurities by condensation from smoke in filtered and unfiltered cigarettes. This disposable structure is made from a fine metallic wire coiled to form a disc-like wafer. While the arrangements described in these patents provide some cooling and adsorption of harmful smoke constituents, they do not dissipate heat effectively and, thus, are not likely to maintain the ability to cool smoke effectively prior to filtering during the entire time a cigarette is burning and being smoked.

There is a need, therefore, for a more effective cooling and filtering device capable of significantly reducing the temperature of smoke in a cigarette or other smoking article or device and maintaining a reduced temperature during substantially the entire time the cigarette is burning and being smoked, thereby enhancing the removal of undesirable smoke constituents by a filter.

SUMMARY OF THE INVENTION

It is a primary object of the present invention, therefore, to provide a cooling and filtering device for cigarettes and other smoking articles and devices that is capable of significantly reducing the temperature of smoke in the cigarette or smoking article and maintaining the reduced temperature during substantially the entire time smoke is produced by the cigarette or smoking article.

It is another object of the present invention to provide an integral cooling and filtering device for cigarettes and other smoking articles and devices that maintains an internal temperature that is low enough to optimize the removal of undesirable and harmful constituents of smoke during substantially the entire time the cigarette or smoking article is burning.

It is an additional object of the present invention to provide an integral cooling and filtering device useful for both filtered or unfiltered cigarettes and other smoking articles that employs a filter with an active cooling device to maintain the temperature of smoke produced by the cigarette at an optimally cool temperature to enhance removal of undesirable components of smoke.

It is a further object of the present invention to provide an integral cooling and filtering device for cigarettes and other smoking articles and devices that employs a metal filter and a thermionic cooling device to maintain smoke produced by the cigarette or smoking article at an optimal temperature for removing undesirable and harmful constituents from smoke.

It is yet another object of the present invention to provide a cooling and filtering device for cigarettes and other smoking articles that can be configured either to be permanent with proper cleaning or to be disposable.

It is yet a further object of the present invention to provide an integral cooling and filtering device useful with a wide range of smoking devices to effectively cool and filter the combustion products of the material being smoked and to maintain the temperature of the these products at an optimum temperature for preventing undesirable and harmful constituents from reaching a smoker.

The aforesaid objects are achieved by providing an integral cooling and filtering device designed to be fitted on an end of a cigarette or other smoking article to reduce the temperature of smoke produced by the combustion of the smoking material and to filter the cooled smoke prior to contact with a smoker. The device is configured with a receptacle to hold a cigarette or like smoking article and with a mouthpiece section that directly contacts the smoker's mouth. A cooling section and a filter section are positioned between the receptacle and the mouthpiece section. Temperature reduction and cooling of the smoke is provided by a thermionic cooling means. The filter section can include a substantially permanent cleanable filter or a replaceable filter. The mouthpiece section may be a heat-resistant metal, plastic, or another appropriate mouth contact material, while the receptacle and cooling and filtering sections are preferably formed of a suitable metal.

Other aspects of the cooling filter of the present invention will become apparent from the following description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic longitudinal cross-sectional view of a cooling filter in accordance with the present invention;

FIG. 2 is a schematic diagram of a thermionic cooling means for cooling combustion products of smoking materials in the cooling filter of the present invention; and

FIG. 3 is a schematic longitudinal cross-section of a cooling filter in accordance with the present invention with a cigarette in place showing the path of smoke through the cooling filter.

DESCRIPTION OF THE INVENTION

Depending on the kind of smoking material being smoked and the puffing intensity with which smoking occurs, the temperature inside commonly available cigarette filters has been found to range from about 25° C. (77° F.) to about 100° C. (212° F.). At temperatures in these ranges, undesirable and harmful constituents intended to be removed from cigarette smoke may be initially removed by widely used filter material, but may then be partly desorbed from the filter material and returned to the smoke. Reducing the temperature of the burning portion of a cigarette or similar smoking article has been indicated to cause a reduction in the production of harmful tars. Cooling the smoke should also enhance adsorption of undesirable smoke constituents by a cigarette filter as well as prevent the desorption of these constituents that results from the high temperatures reached in the filter. As noted above, available filtering and cooling devices for smoking articles have drawbacks. The cooling and filtering device for cigarettes and similar smoking articles of the present invention overcomes these drawbacks and presents an efficient, reliable cooling and filtering device capable of producing and maintaining an optimum temperature to enhance removal of undesirable and harmful constituents from the combustion of smoking materials.

Referring to the drawings, FIG. 1 illustrates schematically a longitudinal cross-section of a cooling filter 10 according to the present invention. This cooling filter 10 is intended to be fitted on an end of a cigarette or similar smoking article, as shown in FIG. 3, and to be inserted into the mouth of a smoker. The cooling filter 10 includes a receptacle 12 with an opening 13 having a diameter d that is sized to receive a typically sized cigarette. The edges of the opening can be substantially parallel or slightly flared, as shown in FIG. 1, and could include ribs (not shown) or other suitable structure to hold the cigarette more securely within the receptacle. Some small cigars may also have diameters similar to those of cigarettes and will fit into the receptacle 12 when diameter d has been selected to accommodate cigarettes. The cooling filter of the present invention can be formed with a different diameter d having a size selected to hold cigars or any other smoking article. The length l of the receptacle 12 should be selected so that enough of the cigarette or other smoking article will be securely supported within the receptacle and will not fall out easily as the cigarette or other smoking article is smoked.

At an end opposite the receptacle 12, a mouthpiece section 14 is provided. The mouthpiece section 14 is designed to have a shape that may be comfortably held in a smoker's mouth. Mouthpieces with suitable shapes that achieve this function are available, and a desired shape may be selected to form the mouthpiece section 14. The length of the mouthpiece section does not affect the function of the cooling filter, and a range of mouthpiece section lengths may be used for the present cooling filter. A cooling section 16 is located adjacent to the receptacle 12, and a filter section 18 is located between the cooling section and the mouthpiece section 14.

The cooling filter of the present invention may be constructed to be a substantially permanent, cleanable and reusable device or a device that is intended to be used for a very limited period of time and then discarded. If the cooling filter is intended for limited use, the connections between the receptacle, cooling section, filter section, and mouthpiece section, designated, respectively, 11, 19, and 21, may be formed differently than if reuse of the cooling filter is intended. The receptacle and the other sections may be formed as an integral unit in a disposable cooling filter, since they do not require separation for cleaning or otherwise. If the cooling filter is intended to be a substantially permanent, cleanable, and reusable device, the respective connections 11, 19, and 21 between the receptacle, cooling section, filter section, and mouthpiece section will be formed to permit separation and detachment of these components for easy access and cleaning. One convenient type of connection is a threaded connection, wherein mating threads are provided on adjacent sections, which are appropriately sized for threaded engagement. Other separable connections, such as, for example, press fitted configurations and releasable detents, are known and may also be used for this purpose.

It is preferred that the receptacle, cooling section, and filter section be made of a metal that is preferably heat resistant, but is also capable of being configured to filter and trap undesirable or harmful constituents of smoke and is sufficiently lightweight to be held comfortably during smoking. Aluminum is one suitable metal. Copper has been used to filter smoke and may also be employed in the present invention. Any other metal suitable for this purpose is also intended to be within the scope of the present invention. The metal selected for the filter section should readily trap tar, nicotine, and other undesirable and/or harmful combustion products of tobacco and should, in addition, be capable of being cleaned to remove these trapped materials if the filter section is to be reusable and substantially permanent. Alternatively, the receptacle and the filter section may be formed of metal, and the cooling section and mouthpiece section may be formed of a suitable plastic or like material. Other combinations of materials are additionally intended to be within the scope of the present invention.

The cooling section 16 employs a unique cooling device 20 that effectively reduces the temperature of the smoke and combustion products of the tobacco or other smoking material in the cigarette or like smoking article when the smoke passes through the cooling section 16. This preferred cooling device, which employs thermionic technology to cool the combustion products and smoke, is shown schematically in FIG. 2. The cooling device 20 employs nanotechnology and works on a subatomic level, using electron migration to reduce heat. Electrons are moved across a gap, which acts as an insulator, to trap heat on one side of the gap and to prevent the return flow of heat by conduction. Devices which accomplish this to produce cooling on a nanoscale are available under the name COOL CHIPS™ These thermotunneling gap diode devices, which function like microscopic heat pumps, are described in U.S. Pat. No. 7,589,348 and European Patent Publication No. 1009958, both of which are owned in common with the present invention and the disclosures of which are incorporated herein by reference.

A representation of a gap diode device 20 suitable for use in a cooling filter for cigarettes and other smoking articles appears in FIG. 2. The device, which is small enough to fit within the diameter of a typical cigarette, includes a pair of electrodes 22 and 24 separated by spacers 26 to create a gap 28 between the electrodes, which are held together by a bond pad 30. An active area 32, in heat transfer contact with electrode 22, represents whatever is to be cooled, in the present invention smoke from a burning cigarette or other smoking article. Another active area 34, in heat transfer contact with electrode 24, represents a heat sink to which heat is transferred, in the present invention preferably at least one heat sink structure 15 within the cooling section 16. The heat sink structure 15 should be located with respect to the receptacle so that heat is not readily transferred to metal forming the receptacle to avoid heating any part of the receptacle that is likely to come into contact with a smoker's fingers. The location of heat sink 15 shown in FIG. 1 is only one possible location. Other locations may also be used effectively to lower the temperature of the smoke passing through the filter device.

Heat transfer from the hot smoke 32 through the thermotunneling gap diode 20 to the heat sink structure 15 follows the path indicated by arrows 40, 42, and 44. The application of an external voltage or an electric field is required to produce a tunneling current and thus achieve the cooling described. This may be accomplished, for example, by a heat activated nano-sized battery 17 in contact with one of the electrodes 22 or 24 in the thermotunneling gap diode 20. Other nanoscale structures sized to fit within the cooling section 16 or in another convenient location in the present device capable of applying an external voltage to the gap diode 20 could also be employed.

The filter section 18 is preferably spaced a sufficient distance from the cooling section gap diode 20 to ensure that the smoke flowing into the filter section has been cooled and the undesirable and harmful smoke constituents will be trapped in the filter section and removed from the cooled smoke. As discussed above, the filter section is preferably a filter element formed of metal configured to trap these constituents. Filter configurations able to trap tar, nicotine, and carbon monoxide are available. Filter sections with filter elements intended to be cleaned and reused should also be configured so that they may be easily removed from the cooling filter for cleaning and easily replaced after cleaning. A wide range of filter configurations may be used to effectively form the filter section of the present cooling filter. The entire filter section 18 may be configured to function as a filter element or, alternatively, a separate filter element (not shown) may be positioned in the filter section to contact cooled smoke from the cooling section 16.

FIG. 3 shows the cooling filter 10 of the present invention with a cigarette 50 inserted into the opening 13 of the receptacle 12. The cigarette is lighted to start combustion of the tobacco or other smoking material in the cigarette. As the smoker puffs on the cigarette, smoke is drawn through the cigarette along a path represented by arrow 52 into the receptacle portion of the cooling filter 10 and into the cooling section 16. Hot smoke flowing through the cooling section 16 will generally follow a path represented by arrow 54 to contact the thermotunneling gap diode cooling device 20. The hot smoke 54 contacts the cooling device 20, and heat is removed, cooling the smoke to a temperature that will enhance the removal of undesirable and harmful constituents of the smoke. The cooled smoke, represented by arrow 56 flows from the cooling section 16 to the filter section 18, where these undesirable constituents are trapped and removed from the cooled smoke before it flows into the mouthpiece section 14 along a path represented by arrow 58 and then into the smoker's mouth.

The cooling and filtering device of the present invention may be effectively used to cool filtered or unfiltered cigarettes. When filtered cigarettes are inserted into the receptacle 12, the smoke produced by the burning tobacco will be initially filtered by the filter material that is attached to the cigarette, then cooled by the cooling device 20, and further filtered by the filter section 18 before entering a smoker's mouth. While the present cooling and filtering device effectively cools and filters the smoke produced by cigarettes, it can also be used to cool and filter the smoke produced by cigars. In addition, the stem of a pipe may be modified to insert a cooling section and a filtering section to cool and filter the smoke from the pipe bowl before it reaches the pipe mouthpiece and a smoker's mouth. Although hookas and similar water pipes cool smoke with water, the mouthpiece end of the hooka tubing may be also be modified to further cool and filter the smoke produced by the hooka before it reaches a smoker's mouth.

The smoking material most likely to be burned and the combustion products cooled and filtered by the cooling filter of the present invention will be tobacco. The present invention may additionally be used to cool and filter the smoke from any type of smoking material, such as, for example, marijuana that can be smoked legally for medical reasons in some jurisdictions.

The present cooling filter for cigarettes and other smoking articles has been described with respect to preferred embodiments. Other, equivalent, structures and processes are also contemplated to be within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention will find its primary applicability where it is desired to provide structure and method for significantly reducing undesirable and harmful constituents produced by the smoke generated by cigarettes and other smoking articles and thereby reducing the levels of these constituents in the smoke that contacts a smoker's mouth. 

1. A device for cooling and filtering smoke produced by the combustion of a material to be smoked comprising a. receptacle means for receiving and holding a smoking article including a combustible smoking material to be burned to produce smoke and smoked by a smoker; b. cooling means in heat transfer contact with smoke produced by burning said smoking material designed to transfer heat from said smoke, thereby cooling said smoke; c. filter means positioned in filtering contact with smoke cooled by said cooling means and configured to trap undesirable constituents desired to be removed from the cooled smoke; and d. mouthpiece means connected to said filter means for directing cooled and filtered smoke to a smoker's mouth.
 2. The device of claim 1, wherein said cooling means comprises thermionic cooling means sized to be positioned within a cooling section of said device between said receptacle means and said filter means.
 3. The device of claim 1, wherein said receptacle means and said filter means are formed of a metal.
 4. The device of claim 1, wherein said filter means comprises a removable, cleanable element.
 5. The device of claim 1, wherein said mouthpiece means is formed of a heat-resistant plastic material.
 6. The device of claim 2, wherein said thermionic cooling device comprises a thermotunneling gap diode.
 7. The device of claim 1, wherein said receptacle means, said cooling means, said filter means, and said mouthpiece means are formed as an integral structure designed to be used for a period of time and then discarded.
 8. The device of claim 1, wherein said cooling means is removably connected to said receptacle means and to said filter means and said filter means is removably connected to said cooling means and to said mouthpiece means, whereby said receptacle means, said cooling means, said filter means, and said mouthpiece means can be separated from each other for cleaning or replacement.
 9. The device of claim 1, wherein said smoking article is selected from the group comprising cigarettes and cigars and said receptacle means is sized to hold said selected smoking article.
 10. The device of claim 1, wherein said smoking article comprises a pipe and said receptacle means is modified to connect the cooling and filtering device to a stem of said pipe.
 11. A device for cooling and filtering combustible smoking material in a smoking article comprising: a. a receptacle sized to receive and hold a smoking article comprising combustible smoking material selected to be smoked by a smoker of said smoking article; b. a cooling section comprising thermionic cooling means in heat transfer contact with smoke produced by burning said combustible smoking material in said smoking article and designed to transfer heat from said smoke; c. a filter element positioned in filtering contact with smoke cooled by said thermionic cooling means and configured to trap undesirable constituents desired to be removed from the cooled smoke; and d. a mouthpiece connected at one end to said filter and shaped at an opposite end to be held in a smoker's mouth, wherein said receptacle, said cooling section, said filter element, and said mouthpiece are all configured to direct the passage of smoke from said smoking article to the smoker's mouth.
 12. The device of claim 11, wherein said thermionic cooling means comprises a pair of nanoscale-sized electrodes separated by spacers to create a gap therebetween, a first active area in heat transfer contact with smoke to be cooled and one of said pair of electrodes, and a second active area in heat transfer contact with another of said pair of electrodes, wherein said second active area comprises a heat sink.
 13. The device of claim 12, further comprising a heat activated nano-sized battery in contact with one of said pair of electrodes.
 14. The device of claim 11, wherein said filter element comprises a filter element that is reusable or a filter element that is disposable.
 15. The device of claim 11, wherein said receptacle, said cooling section and said filter element comprise a heat resistant metal and said mouthpiece comprises a plastic material.
 16. The device of claim 11, wherein said receptacle is connected to said cooling section, said cooling section is connected to said filter element, and said filter element is connected to said mouthpiece by mating threaded connections.
 17. The device of claim 11, wherein said receptacle, said cooling section, said filter element, and said mouthpiece are formed as an integral structure designed to be used for a period of time and then discarded.
 18. The device of claim 11, wherein said receptacle is sized to hold smoking articles comprising cigarettes, cigars, pipes, or hookahs. 